Payment dispute

I ordered from KFC on the Uber eats app on 13 December at 17:30, the order only came at 8 I had left the house to go get food by the time the driver arrived. I asked him to add the bill to my next order as I was a bit far. Driver(Jabulani) left with the order and Uber eats wants me to pay for it...WHY??? The app was no help BTW.